Impact of Inflow Ratio on a Double-Inflow Cavopulmonary Assist Device.

Hepatic Venous Occlusion During Cardiopulmonary Bypass in Patients With Heterotaxy Syndrome: A Safe but Underutilized Option

We wished to determine whether the individual bias (mean difference) and precision (standard deviation of the difference) values of 2 variables, arterial oxygen saturation (SaO2) and mixed venous oxygen saturation (SvO2), could be used to predict the bias and precision values of the combined dual oximetry variable (SaO2-SvO2). We simultaneously measured SaO2 by pulse oximetry and arterial blood gas co-oximetry and SvO2 by fiberoptic reflectance oximetry pulmonary artery catheter and venous blood gas co-oximetry in 238 data sets from 55 patients. Three different methods were used to predict the standard deviation of the difference of (SaO2-SvO2) [s delta(SaO2-SvO2)]: simple sum, root mean square (RMS) error, and RMS error with correction term. We derived the equation for the RMS error with correction term because initial results showed that the simple sum and RMS error methods did not predict s delta(SaO2-SvO2) well. The correction term accounts for the non-independence of simultaneous SaO2 and SvO2 measurements. The observed overall bias of the SaO2, SvO2, and (SaO2-SvO2) measurement methods were 0.17, -1.76, and 1.94, respectively. The observed overall s delta(SaO2-SvO2) of the (SaO2-SvO2) measurement method was 5.12. The simple sum method overestimated the actual s delta(SaO2-SvO2) by 38%, the RMS error method differed from the actual s delta(SaO2-SvO2) by 3%, and the RMS error with correction term method matched the actual s delta(SaO2-SvO2). The bias of a (SaO2-SvO2) measurement method is simply the bias of the SaO2 measurement method less the bias of the SvO2 measurement method. s delta(SaO2-SvO2) is best predicted by the derived equation, RMS error with correction term. The same principles and equations also apply to other situations in which 2 variables with the same dimensions are combined into 1 variable, such as (PaCO2-EtCO2) gradients and perfusion-pressure gradients. Although the difference between the s delta(SaO2-SvO2) predicted by the RMS error equation and the derived RMS error equation with correction term was small, the difference may be significant for other combined variables.

This study was conducted at Laman Sayur, Malaysia Agro Exposition Park Serdang (MAEPS), to investigate the hydraulic performance of a small-scale drip irrigation system. The modelling was carried out using EPANET software to understand how the drip irrigation system is operated. Model results show that the errors are small, i.e., 2.2% and 3.0% for pressures, and 1.7% for discharge in lateral pipe 1 and lateral pipe 2. The root mean square error (RMSE) and the mean bias error (MBE) for discharge were recorded at 0.04 L/h and 0.03 L/h for lateral pipe 1 and 0.04 L/h and 0.02 L/h for lateral pipe 2. RMSE and MBE for pressure were recorded at 0.61 m and 0.68 m for lateral pipe 1, and 0.79 m and 0.68 m for lateral pipe 2, respectively. These results show that the model yields good performance. For hydraulic performance, the field measurement was conducted with four operating pressures: P1 (15.3), P2 (20.4), P3 (25.5), and P4 (28.6) meters. The hydraulic parameters evaluated were the coefficient of uniformity (CU), the emission uniformity (EU), the coefficient of variation (CV), and the emitter flow variation (EFV). The operating pressure during the measurement is constant according to the specified pressure. The results show that CU, CV, and EU are in the excellent classification, and values of CU and EU have more than 95% efficiency. The value for CV is below 0.03, which is excellent. The EFV is 10% when operating at 25.5 m and 15.3 m and is considered desirable. On the other hand, for the 28.6 m and 15.3 m operating pressures, the EFV parameters were recorded at 13.6% and 10.29%, respectively, and are classified acceptable. This study concluded that the operating pressures, P2 (20.4 m) and P3 (25.5 m), were performed under excellent classification for all hydraulic parameters evaluated. Based on the outputs from the model, it is inferred that the existing drip irrigation system at Laman Sayur MAEPS is operated in an over-powered state. With the current pump power consumption, the irrigation system could be operated at a minimum of four times the capacity of the existing irrigation system. To reduce the power consumption, it is suggested that the system is operated at a lower pumping power. This would minimize the operating costs especially for the development of a new drip irrigation system that has the same capacity as the drip irrigation system that is currently being operated at Laman Sayur, MAEPS Serdang.

Implantable left ventricular assist devices provide circulatory support for patients at risk of death from refractory, end-stage heart failure. Rotary blood pumps have been designed for increased reliability and smaller size for use in a broader population of patients than the first-generation pulsatile devices. The design concepts and principle of operation of the HeartWare System are discussed. The HeartWare Ventricular Assist System (HVAD) is a small centrifugal flow pump with a displacement volume of 50 ml and an output capacity of 10 L/min. A unique wide-blade impeller is suspended by hybrid passive magnets and hydrodynamic forces. An integrated inflow cannula is inserted into the left ventricle and is held in position by an adjustable sewing ring; the pump is positioned in the pericardial space. The 10-mm outflow graft is anastomosed to the ascending aorta. External system components include the microprocessor-based controller, a monitor, lithium-ion battery packs, alternating current and direct current power adapters, and a battery charger. Physiologic control algorithms are incorporated for safe operation. Preclinical life cycle tests have shown the HVAD to be highly reliable. This system design offers reliability, portability, and ease of use for ambulatory patients.

BACKGROUNDRecently, as a possible therapy resolving solution, pentadecapeptide BPC 157 therapy, has been used in alleviating various vascular occlusion disturbances. BPC 157 was previously reviewed as novel mediator of Robert cytoprotection and endothelium protection in the stomach, and gut-brain axis, beneficial therapy in gastrointestinal tract, with particular reference to vascular recruitment, ulcerative colitis and tumor cachexia, and other tissues healing. Here we raised new hypothesis about BPC 157 therapy in the Budd-Chiari syndrome in rats, rapid bypassing of the suprahepatic inferior caval vein occlusion, and rats recovery with the active and effective pharmacotherapy treatment.AIMTo investigate Budd-Chiari syndrome model (inferior caval vein suprahepatic occlusion) resolution, since BPC 157 resolves various rat vascular occlusion.METHODSWe assessed the activated bypassing pathways between the inferior and superior caval veins and portocaval shunt, counteracted caval/portal hypertension, aortal hypotension, venous/arterial thrombosis, electrocardiogram disturbances, liver and gastrointestinal lesions (i.e., stomach and duodenum hemorrhages, in particular, congestion). Rats with suprahepatic occlusion of the inferior vena cava by ligation were medicated at 1 min, 15 min, 24 h, or 48 h post-ligation. Medication consisted of 10 µg/kg BPC 157, 10 ng BPC 157 or 5 mL/kg saline, administered once as an abdominal bath or intragastric application. Gross and microscopic observations were made, in addition to assessments of electrical activity of the heart (electrocardiogram), portal and caval hypertension, aortal hypotension, thrombosis, hepatomegaly, splenomegaly and venography. Furthermore, levels of nitric oxide, malondialdehyde in the liver and serum enzymes were determined.RESULTSBPC 157 counteracted increased P wave amplitude, tachycardia and ST-elevation, i.e., right heart failure from acute thrombotic coronary occlusion. The bypassing pathway of the inferior vena cava-azygos (hemiazygos) vein-superior vena cava and portocaval shunt occurred rapidly. Even with severe caval ˃ portal hypertension, BPC 157 antagonized portal and caval hypertension and aortal hypotension, and also reduced refractory ascites. Thrombosis of portal vein tributaries, inferior vena cava, and hepatic and coronary arteries was attenuated. In addition, there was reduced pathology of the lungs (severe capillary congestion) and liver (dilated central veins and terminal portal venules), decreased intestine hemorrhagic lesions (substantial capillary congestion, submucosal edema and architecture loss), and increased liver and spleen weight. During the period of ligation, nitric oxide- and malondialdehyde-levels in the liver remained within normal healthy values, and increases in serum enzymes were markedly reduced.CONCLUSIONBPC 157 counteracts Budd Chiari syndrome in rats.

Land surface temperature (LST) retrieval from NOAA-AVHRR data is mainly through so-called split window algorithms. During the last 20 years 17 split window algorithms has been published. These algorithms can be grouped into four categories: emissivity-dependent models, two-factors models, complicated models and radiance model. In this paper we intend to compare these split window algorithms in terms of their computation and accuracy. Two methods are used for the comparison: ground datasets and simulation datasets. Results from comparison shows that different algorithms have different performances under different situations. For simulation datasets, the algorithms of Qin et al. and Sobrino et al. are the best. The average root mean square (RMS) error of the two algorithms is less than 0.3degC. The algorithms of Franca and Cracknell, Prata and Uliverir et al. also have very low RMS errors (0.5-0.7degC). Results from comparison with ground datasets indicates that the algorithms of Qin et al. and Sobrino et al. are among the best for the dataset without precise in situ atmospheric water vapor contents. These algorithms are able to provide LST retrieval with average RMS error less than 1.9degC for the 361 measurements of the two Australian sites. An obvious contrast to the generally higher RMS error for the dataset is the much lower RMS error of the algorithms for the intensive experiments with precise in situ atmospheric water vapor contents. Based on the above two methods for comparison, it can be concluded that, comprehensively, the algorithm of Qin et al. is the best alternative for LST retrieval from AVHRR followed by Sobrino et al., Franca and Cracknell, and Prata when data are available to estimate both emissivity and transmittance

In this manuscript, an efficient trim analysis technique is presented for CFD analysis in level flight of coaxial rotors. Trim analysis of coaxial rotors requires a lot of computational resources to obtain gradients of control variables. Blade Element Theory as an efficient alternative method is applied to the computation of control variable gradients. The inflow ratios of upper and lower rotors are obtained from CFD results. These values include aerodynamic interference between upper and lower rotors. Using the inflow ratio from CFD results, Blade Element Theory can take the accurate direction to the trim state. The presented method is validated through the experiments of Dingeldein, and it is confirmed that the trim analysis results are consistent with experimental results and other analysis results.

Some data into combined and sanitary sewer system were collected in order to find out the characteristics of discharge from first flush rainfall inflow. The inflow ratios of combined and sanitary sewer system were 0.46 and 0.27 during rains from various survey data. The average inflow ratio 0.31 was appropriate for general application because many watersheds were not classified clearly as combined or sanitary sewage treatment areas. The percentage of first flush loads in the whole BOD load was about 10%. This result was thought some meaningful, comparing with similarity of first flush pollution load contribution previous surveyed by KECO (2004).

Pit lake oxygen and hydrogen isotopic composition in subarctic Sweden: A comparison to the local meteoric water line

SummaryBackgroundHistological changes of the lungs were studied after the establishment of a modified total cavopulmonary connection (TCPC) without the use of cardiopulmonary bypass (CPB) or other means of temporary bypass on a swine model.Material/Methods8 open chest-anesthetized pigs Landrace × Large White pigs (mean weight 43kg, mean age 4.5 months) underwent TCPC by the use of an appropriate size Y-shaped conduit connecting the superior and inferior caval veins (end-to-end anastomosis) to the pulmonary trunk (end-to-side anastomosis). After sternotomy, a wedge resection of the lung parenchyma was performed at baseline. Hemodynamic stability was sustained after TCPC establishment and 2 hours later another wedge resection of the lung was performed (from the same anatomic area). Histological studies were conducted by hematoxylin and eosin staining.ResultsAll samples (n=8) at baseline were consistent with normal lung parenchyma. After the establishment of TCPC, all samples (n=8) revealed moderate mononuclear infiltration adjacent to pulmonary alveoli and bronchioles, findings compatible with bronchiolitis.ConclusionsIn a normal swine model, 2 hours after the establishment of Fontan circulation without the use of CPB, pathologic examination of the lungs revealed bronchiolitis. Further research is needed to clarify these findings and the potential implications to the Fontan circulation, either immediate or long-term.

Accurately measuring river flow is not only crucial for hydrologists monitoring hydrological processes but also important for all professionals involved in hydrological research. The ultrahigh frequency (UHF) band enables the surface flow velocity measurement at a deeper effective water depth, so it is less susceptible to the influence of wind drift. However, in curved river channels, the spatial variation in surface velocity is caused by the uneven erosion of the water flow, and this variation is influenced by both air shear stress and the curvature of the river. To mitigate the impact of water level on cross-sectional flow velocity estimation and address the nonlinear relationship between cross-sectional area and water level, this paper proposes a model that is independent of river water level. The nonlinear relationship between cross-sectional area and water level is calculated using a Taylor series expansion. The model was validated using experimental data collected from the Xiantao section of the Han River in Hubei, China, from March to July 2018. The data were discussed separately for high-flow and low-flow periods and were divided into training and validation sets in an 8:2 ratio. Compared to the previous method, our improved method reduces the Root Mean Square Error (RMSE) and Mean Absolute Percentage Error (MAPE) by approximately 2%. In the estimation of flow during the dry season, the improved method achieved a correlation coefficient of 0.9523, representing an increase of 0.1243 compared to the original method. The RMSE was 23.0383, and the MAPE was 0.0232, showing reductions of 23.144 and 0.0241, respectively, compared to the original method. In the estimation of discharge during the wet season, the improved method achieved a correlation coefficient of 0.9908, an increase of 0.0575 compared to the original method. The RMSE was 65.4929, and the MAPE was 0.0391, reflecting reductions of 75.1271 and 0.0338, respectively, compared to the original method. This advancement further enhances the application of UHF radar for discharge measurement in meandering rivers.

In this study, the CCHE2D model was used to analyze the flow patterns in Tigris River in Baghdad city around a water treatment plant. To this end, the model was calibrated and validated in a steady-state using the relevant boundary conditions. The model was calibrated using the initial water surface level at the Sarai station for three discharges of 289, 530, and 870 m3/s. Hence, appropriate manning roughness modulus and equivalent mixing length turbulent models were selected to construct the hydraulic model of the Tigris River. The model was validated using the Root Mean Square Error (RMSE), mean absolute error (MAE), and coefficient of determination (R2) equations. Results show that the RMSE, MAE, and R2 between the observed and modelled water levels at Sarai station were (0.17, 0.12, 0.9) m respectively during the validation. It was found that the average water velocity around the studied intake was 0.4 to 0.8 m/s while the water levels were 29 to 30 m. The CCHE2D model proved its capability to simulate the hydraulic behavior of the Tigris River. This study could be of use for further analysis on the hydraulic performance and provide better insights towards better management of the river.

Intra-abdominal pressure (IAP) can be measured in different ways but is usually measured indirectly via the urinary bladder. The aim of the study was to: 1) compare urinary bladder pressure, femoral vein pressure, and inferior caval vein pressure with IAP at different levels of IAP; and 2) try to find an optimal amount of fluid to be instilled into the urinary bladder before measurement of the bladder pressure, and to compare changes in blood flow in the femoral vein with that in the caval vein at different pressure levels. Experimental study. Animal research laboratory. Eight domestic swine of both sexes, weighing 30.6+/-2.9 kg (mean+/-SD). Catheters connected to pressure transducers were placed into the urinary bladder, the inferior caval vein, the femoral vein, and the superior caval vein. Transit time flow probes were placed around the inferior caval vein and the femoral vein. After a stabilizing period, the abdominal pressure was increased stepwise by instillation of Ringer's solution into the abdomen and then decreased. Thereafter, we instilled fluid into the bladder at an IAP of 8 mmHg and at 20 mmHg and measured the amount of fluid needed to elevate the intra-vesical pressure by 2 mmHg. The pressures recorded in the urinary bladder, the inferior caval vein, and the femoral vein reflected the pressure in the abdominal cavity very well. The fluid volume needed to increase the bladder pressure by 2 mmHg was significantly lower at 20 mmHg IAP than at 8 mmHg. Blood flow in the femoral vein and the inferior caval vein showed a similar pattern and decreased when the intra-abdominal pressure increased. In our porcine model, and increasing the IAP by means of instillation of Ringer's solution, a reliable estimation of the IAP was obtained by measuring the pressure in the urinary bladder, the femoral vein or the inferior caval vein. The IAP estimated indirectly as the urinary bladder pressure is affected by the amount of fluid in the bladder, which should not exceed 10-15 ml. The decrease in femoral vein blood flow reflects the changes in inferior caval vein flow during increased IAP.

To demonstrate the use of transthoracic contrast echocardiography in the detection of pulmonary arteriovenous fistulas in patients with a previously constructed anastomosis between the superior caval vein and the right pulmonary artery (Glenn shunt), and to examine their prevalence in this special population, we evaluated prospectively all patients followed up in the Grown-Up Congenital Heart Unit subsequent to construction of a classical or bi-directional Glenn shunt. We studied 12 patients, aged from 21 to 38 (mean 28 ± 4.8) years who had had a previous cavopulmonary shunt in place for a period of 4 to 33 years (mean 24±9 years). All were examined with cross-sectional contrast echocardiography, 11 patients had cardiac catheterisation and angiography, and 6 patients had magnetic resonance imaging. Systemic arterial oxygen saturations at rest, and during exercise using the modified Bruce protocol, were measured in all patients. Contrast echocardiography showed evidence of pulmonary arteriovenous fistulas in 7 of the 12 patients, with appearance of echo contrast in the left atrium 1–8 seconds after peripheral venous injection in the arm. Simultaneous appearance of microbubbles in the right atrium revealed a residual communication between the superior caval vein and the right atrium in 2 patients, and presence of collaterals between the superior and inferior caval veins in one. Cardiac catheterisation and angiography showed obvious fistulas in 4 patients, and revealed suggestive findings in 2. In patients deemed to have pulmonary arteriovenous fistulas on contrast echocardiography, arterial oxygen saturations at rest (51–94%, mean 75±15.3%) and on exercise (23–91%, mean 53±24.2%) were significantly lower compared to patients judged to be without fistulas (p<0.005). Pulmonary hypertension in the contralateral lung was more common in patients with fistulas (mean left pulmonary arterial pressure 22–110 mm Hg, p=0.014). In patients with cavopulmonary anastomoses, pulmonary arteriovenous fistulas occur frequently in the long term (10–33, mean 25.7±8 years), and are associated with worsening systemic arterial desaturation. Contrast echocardiography should be included in the regular evaluation of these patients as a simple and sensitive technique for the detection of pulmonary arteriovenous fistulas, particularly with the devel opment of increasing cyanosis.

This paper proposes a new Asian single site tropospheric correction model called the Single Site Improved European Geostationary Navigation Overlay Service model (SSIEGNOS) by refining the European Geostationary Navigation Overlay Service (EGNOS) model at a single site. The performance of the SSIEGNOS model is analyzed. The results show that (1) the bias and root mean square (RMS) error of zenith tropospheric delay (ZTD) calculated from the EGNOS model are 0.12 cm and 5.87 cm, respectively; whereas those of the SSIEGNOS model are 0 cm and 2.52 cm, respectively. (2) The bias and RMS error show seasonal variation in the EGNOS model; however, little seasonal variation is observed in the SSIEGNOS model. (3) The RMS error decreases with increasing altitude or latitude in the two models; however, no such relationships were found in the bias. In addition, the annual predicted bias and RMS error in Asia are −0.08 cm and 3.14 cm for the SSIEGNOS model, respectively; however, the EGNOS and UNB3m (University of New Brunswick) models show comparable predicted results. Relative to the EGNOS model, the annual predicted bias and RMS error decreased by 55% and 48%, respectively, for the SSIEGNOS model.